1. Field of the Invention
The invention relates generally to methods and devices for packaging products and particularly to methods and devices for packaging products in bags while deflating the bag to remove unwanted headspace gases.
2. Description of the Related Art
Machines and devices for deflating packages are known in the art. U.S. Pat. No. 4,964,259 discloses a process and apparatus for forming, filling, sealing and deflating a package of goods prior to the time the fill opening is sealed includes a blast of air against the exterior flexible sidewalls of the package to thereby drive gas from the inside of the package. U.S. Pat. No. 5,210,995 discloses a machine for packaging objects, particularly containers comprising a frame having a conveyor belt and a pair of convergent tracks leading to a distributing means, at least two containers to be joined in a package, and means moving said containers towards a third track with vertically disposed reels feeding laminar material to opposite sides of the containers, and through cutting and thermowelding means which form the package for inserting it in the heating tunnel. U.S. Pat. No. 5,303,531 discloses a packaging apparatus and method for packaging objects in such a way as to ensure that the article will not be damaged. Objects to be packaged are gripped by a plurality of pairs of vertically oriented gripping fingers each having inflatable bladders therein. The inflated bladders engage the objects with a predetermined low pressure sufficient to grasp and secure the objects. The plurality of fingers with gripped objects are then moved to place the objects in packaging containers. A vacuum is drawn on the inflated bladders, releasing the objects into the packaging container. US2006120632A1 discloses a vacuum packaging bag wherein three edges of the bag are sealed and one edge is equipped with a concave-convex fastener. The bag is equipped with a deflating device. The deflating device consists of a base, a holding washer, a cover, and a sealing washer. The cover and the based are connected through screw threads. The base is placed inside the bag. The screw part of the base penetrates through one side of the bag. The holding washer fastens the film against the base. The sealing washer is placed on a support. The support is placed in the passageway between the base and the outside of the bag. The middle of the cover has a pressure post which is connected to the sealing washer. The middle of the pressure post has an opening to the outside of the bag. A deflating cylinder is used with the deflating device of the bag. The deflating cylinder is a piston cylinder. The front part of the piston rod has two holding boards. Between the holding boards there is a spacer. The backside board has a notch; the back part of the piston rod is connected to a pulling handle. On the front part of the cylinder is a convex. A pulling ring is attached to the convex. The vacuum packaging bag of the invention is simple in structure, easy to make, and convenient to use. It ensures the stored goods quality and value. US2008209864A1 discloses a process for forming a pouch having an evacuated headspace containing a flowable material. The process includes the steps of: providing a continuous tube of flexible and sealable film; supplying the continuous tube with a predetermined amount of flowable material; pinching the continuous tube above a sealing region so as to form a pinched portion of the continuous tube; evacuating the headspace between the pinched portion and the predetermined amount of flowable material; and sealing the continuous tube at the sealing region to form a top seal of a previously formed pouch containing flowable material and a bottom seal of a next-to-be filled pouch. Also disclosed is a vertical form-fill-seal apparatus for forming a pouch containing a flowable material and having an evacuated headspace.
In a typical bagging operation, a bag having one open end enters a bag filling machine and is engaged by a transfer arm that grips the bag and opens the open end of the bag, typically by pinching the edge of the bag in close proximity to the open end of the bag. The transfer arm pinches the bag on both sides between gripper arms/blocks on the machine's transfer arm. The transfer arm then moves the bag such that a spout on the machine is in a position to fill product into the bag through the open end of the bag. Typically, the spout is surrounded by the open end of the bag.
Spout clamps on the spout engage the bag and hold the bag in a position to be filled with a product that flows from the spout into the bag. The gripper blocks release the bag and return a position to engage the next bag to be filled after the spout clamps engage the bags. The product is filled from the spout through the bag to a desired level. After the bag is filled, the machine transport arm having gripper blocks grips the bag using the gripper blocks and moves it away from the spout to an outfeed conveyor for further processing, e.g., sealing.
The problem with this operation is that the filled bag has air or other gases in the headspace above the product. This air expands the bag, opens gussets, and interferes with sealing and other process. Also, the air can be detrimental to the product, e.g., the air contains moisture that may facilitate microbial growth on the product. Further, the air can make the bag more difficult to handle, e.g., more difficult to palletize and place on the retail shelf. This problem is characteristic of bags, pouches and other similar containers. There is, therefore, a need for new bag deflation devices and methods useful for removing unwanted headspace gases from containers.